serial_mx31: allow it to work with mx27 too and rename to serial_mxc

UART hardware on i.MX27 is the same as on the i.MX31 so we just
need to provide the driver with correct address of the registers.

Signed-off-by: Ilya Yanok <yanok@emcraft.com>
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index ab5d565..64882a2 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -41,7 +41,7 @@
 COBJS-$(CONFIG_LPC2292_SERIAL) += serial_lpc2292.o
 COBJS-$(CONFIG_LH7A40X_SERIAL) += serial_lh7a40x.o
 COBJS-$(CONFIG_MAX3100_SERIAL) += serial_max3100.o
-COBJS-$(CONFIG_MX31_UART) += serial_mx31.o
+COBJS-$(CONFIG_MXC_UART) += serial_mxc.o
 COBJS-$(CONFIG_NETARM_SERIAL) += serial_netarm.o
 COBJS-$(CONFIG_PL010_SERIAL) += serial_pl01x.o
 COBJS-$(CONFIG_PL011_SERIAL) += serial_pl01x.o